Prevent CRD deletion on helm delete

[sfrique]

Hello,

If CRD were created by helm, once you delete flux, it would delete the CRD, this would cause flux to try to delete the charts while it's been terminated.

This PR makes helm do not remove CRD.

$ helm delete --purge flux
These resources were kept due to the resource policy:
[CustomResourceDefinition] fluxhelmreleases.helm.integrations.flux.weave.works
[CustomResourceDefinition] helmreleases.flux.weave.works

release "flux" deleted

I've also bumped the chart.

[stefanprodan]

LGTM

Thanks @sfrique